The present invention relates to a catalyst component for olefin polymerization.
Some catalyst components for olefin polymerization using, as a raw material, a metal oxide such as silica, which are capable of producing polyolefins (e.g., polypropylene) having high stero-regularity and excellent particle characteristics (spherical particles having a narrow particle size distribution) in a high yield, have been proposed.
For example, there are known a catalyst component comprising a reaction product between a metal oxide and a magnesium dialkoxide, an electron donor compound, and a tetravalent titanium halide having contacted with each other (see Japanese Patent Application Kokai No. 162607/1983); and a catalyst component comprising a reaction product between an inorganic oxide and a magnesium hydrocarbyl halide compound, a Lewis base compound, and titanium tetrachloride having contacted with each other (see Japanese Patent Application Kokai No. 94909/1980). However, these catalyst components are not yet satisfactory in activity and stero-regularity.
Further, methods in which a reaction produce between a porous carrier (e.g., silica) and an alkylmagnesium compound is brought into contact with an electron donor compound and a silicon halide compound prior to contacting with a titanium compound are disclosed in Japanese Patent Application Kokai Nos. 115405/1980 and 108107/1982. However, the catalyst components obtained by these methods are not yet satisfactory in performance from the industrial viewpoint.
The present inventors have previously developed catalyst components for polymerization of .alpha.-olefins (particularly propylene or the like) having high activity and stero-regularity, such as (1) a catalyst component comprising a metal oxide, an alkoxy group-containing magnesium compound, an aromatic polyhydric carboxylic acid which is substituted with a carboxyl group at the o-position thereof or a derivative thereof, and a titanium compound having contacted with each other (see Japanese Patent Application Kokai No. 174204/1986); (2) a catalyst component comprising a metal oxide, an alkoxy group-containing magnesium compound, a hydrogen-silicon bond-containing silicon compound, an electron donor compound, and a titanium compound having contacted with each other (see Japanese Patent Application Kokai No. 174205/1985); (3) a catalyst component comprising a metal oxide, an alkoxy group-containing magnesium compound, a halogen element or a halogen-containing compound, an electron donor compound, and a titanium compound having contacted with each other (see Japanese Patent Appliation Kokai No. 174206/1986); (4) a catalyst component comprising a reaction product obtained by bringing a metal oxide and a dihydrocarbylmagnesium into contact with a halogen-containing alcohol, an electron donor compound, and a titanium compound having contacted with each other (see Japanese Patent Application Kokai No. 21109/1986); and (5) a catalyst component comprising a solid which is obtained by bringing a metal oxide and a dihydrocarbylmagnesium into contact with a hydrocarbyloxy group-containing compound, a halogen-containing alcohol, an electron donor compound, and a titanium compound having contacted with each other (see Japanese Patent Application Kokai No. 7706/1987).
However, when the above-described conventional catalyst components are used, a phenomenon that fine powders of polymer are formed during the polymerization is observed. Therefore, such likely introduces a problem into the polymerization method which dislikes the formation of fine powders of polymer, such as the production of polyolefins by means of a fluidized bed. Moreover, realization of catalyst components exhibiting higher activity is being demanded.